[PATCH v5 4/7] tools: Add atomic_test_and_set_bit()
From: Sean Christopherson <seanjc@google.com>
Date: 2022-08-25 23:25:59
Also in:
kvm, kvm-riscv, kvmarm, linux-riscv, lkml, llvm
Subsystem:
the rest · Maintainer:
Linus Torvalds
From: Peter Gonda <redacted>
Add x86 and generic implementations of atomic_test_and_set_bit() to allow
KVM selftests to atomically manage bitmaps.
Note, the generic version is taken from arch_test_and_set_bit() as of
commit 415d83249709 ("locking/atomic: Make test_and_*_bit() ordered on
failure").
Signed-off-by: Peter Gonda <redacted>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
tools/arch/x86/include/asm/atomic.h | 7 +++++++
tools/include/asm-generic/atomic-gcc.h | 12 ++++++++++++
2 files changed, 19 insertions(+)
diff --git a/tools/arch/x86/include/asm/atomic.h b/tools/arch/x86/include/asm/atomic.h
index 1f5e26aae9fc..01cc27ec4520 100644
--- a/tools/arch/x86/include/asm/atomic.h
+++ b/tools/arch/x86/include/asm/atomic.h@@ -8,6 +8,7 @@ #define LOCK_PREFIX "\n\tlock; " +#include <asm/asm.h> #include <asm/cmpxchg.h> /*
@@ -70,4 +71,10 @@ static __always_inline int atomic_cmpxchg(atomic_t *v, int old, int new) return cmpxchg(&v->counter, old, new); } +static inline int atomic_test_and_set_bit(long nr, unsigned long *addr) +{ + GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(bts), *addr, "Ir", nr, "%0", "c"); + +} + #endif /* _TOOLS_LINUX_ASM_X86_ATOMIC_H */
diff --git a/tools/include/asm-generic/atomic-gcc.h b/tools/include/asm-generic/atomic-gcc.h
index 4c1966f7c77a..6daa68bf5b9e 100644
--- a/tools/include/asm-generic/atomic-gcc.h
+++ b/tools/include/asm-generic/atomic-gcc.h@@ -4,6 +4,7 @@ #include <linux/compiler.h> #include <linux/types.h> +#include <linux/bitops.h> /* * Atomic operations that C can't guarantee us. Useful for
@@ -69,4 +70,15 @@ static inline int atomic_cmpxchg(atomic_t *v, int oldval, int newval) return cmpxchg(&(v)->counter, oldval, newval); } +static inline int atomic_test_and_set_bit(long nr, unsigned long *addr) +{ + unsigned long mask = BIT_MASK(nr); + long old; + + addr += BIT_WORD(nr); + + old = __sync_fetch_and_or(addr, mask); + return !!(old & mask); +} + #endif /* __TOOLS_ASM_GENERIC_ATOMIC_H */
--
2.37.2.672.g94769d06f0-goog
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